Flow forming of transmission components, such as clutch housings, is being introduced into the manufacturing process. The current use of this manufacturing form is to provide a tubular shell from a disc member. The internal drive spline teeth are roll formed and the outer diameter is smooth and of singular dimension. At least one process considers forming spline teeth in the outer diameter using a toothed tool member to press the tooth form into the outer diameter after the flow forming operation.
The more common manufacturing processes used in the manufacture of clutch housings is deep drawing, which is a multiple step process or hammer forming, wherein a hammer like tool is used to form a cup-shaped blank formed on a toothed mandrel. Axial roll forming has also been used to manufacture these components. With this process, a cup-shaped blank is mounted on a shaped mandrel, and a roll formed tool moves axially to press the metal to the tooth shape on the mandrel, essentially one tooth at a time. The mandrel is rotated to present the undeveloped surface to the roll form too to allow the entire inner surface to be splined.
The prior art structures have been limited to simple housings while more intricate assemblies, such as a torque tube drive connection in clutch housings used in one commercially available transmission, continue to be multiple piece structures.